This section provides background information related to the present disclosure which is not necessarily prior art.
The first developed computers were based on mechanical logic. In the mid-1800s, Charles Babbage and Ada Lovelace designed the first programmable, Turing-complete computer, the “analytical engine”, based on mechanical logic. A significant challenge with mechanical logic, however, has been the inability to successfully scale down mechanical logic systems to microscale dimensions. While the computing industry quickly moved to electronic logic systems, mechanical logic still offers several advantages. Chief among them, mechanical logic circuits do not require an electrical power source. As a result, computers built using mechanical logic circuit will have a negligible electromagnetic (EM) signature.
Previously developed microscale material logic gates are known as “single use” logic gates. By “single use” logic gates it is meant that the logic gates are useable one time only; they do not allow for the logic circuit to be reset to enable further computation. This significantly limits the applications that such logic gates may be used in. A mechanical logic gate that could be “reset” and used repeatedly would significantly expand the number of potential applications that mechanical logic gates could be used in. For example, multi-use mechanical logic elements could be used to act as simple status sensors for a material, changing an output RF signature (via RFID type technology) based on material stress, temperature, magnetic field, crack propagation or other parameter. This could be combined via the mechanical logic to only change signature upon the receipt of a special sequence of signals. This would act as a micro-scale lock and key system, which could be used to ensure that smart tags on credit cards, passports or other secure devices only respond when desired, for instance, when pressed on. Multi-use low power mechanical circuitry could also be used to effectively provide a means of surveillance. For instance, a micro-scale grain-of-salt sized radiologically activated circuit could trigger given the absorption of a particular kind of radiation, mechanically switching an RFID loop to change to response pulse. Now, when pulsed, the sensors which have observed the radiation will return an adjusted frequency. A simple hand-held RFID reader could pulse an area and get an exact reading of where the radiological source has been. Resettable circuits allow for real time position location, as when the source moves on by, the mechanical logic turns itself back off. With the resettable microscale logic gates, RF pulses would only return sensors readings next to the present location of the source, providing a real-time read-out of source location. This could similarly be done for tracking other signals, including temperature, chemicals, or mechanical load. For example, hydrogen sensitive circuits could be seeded around a hydrogen processing facility, even mixed into the paint. A quick scan with an RF reader would immediately determine the status and location of any gas leaks. Such sensors could be deployed by a method akin to crop dusting over a gas leak to monitor the gas plume location (if invisible) in real-time. The mechanical logic provides a means to transfer from one sensing domain, located in microscale structures and possibly widely distributed over the environment, to another domain. This second domain could well be radiation (RF), so that the scanning and information retrieval could be done at remotely. More complex information capture mechanisms, such as audio or other signal recording are also possible with more extensive mechanical logic. These records could be transmitted back to the RF source upon radio interrogation. This would provide an easy means to check for intrusion or tampering in a device, even if the device is later reset.
The present invention could be applied to low power sensing applications, environmental monitoring and logging of temperature or humidity cycling. Due to the small size of the logic gates and no electrical consumption, they can be easily concealed within the structure of a material and perform computing operations clandestinely. For example, monitoring diurnal temperature variations at a location. Furthermore, microscale mechanical logic gates could form the basis of materials that sense and respond to their environment, or so-called sentient materials. For example, in oil, gas, and geothermal wells, rock formation temperature and pressure are important metrics for operation. Microscale mechanical logic circuits could be built into small particles, creating “smart dust”, that could be injected into the well. The smart dust could be programmed to trigger release of a chemical that can be sensed at an extraction well when certain thresholds in pressure and temperature are simultaneously crossed, thus providing critical information that is difficult to determine by other means.